#include <iostream>
#include <chrono>
#include <ctime>

using namespace std;

int shulie(int n)
{
    if (n == 1 || n == 2)
    {
        return 1;
    }
    return shulie(n - 1) + shulie(n - 2);
}

int main()
{
      /* 记录起始时间 */
    auto start = std::chrono::steady_clock::now();
    cout << shulie(40) << endl;
    /* 记录结束时间 */
    auto end = std::chrono::steady_clock::now();

    /* 计算时间差 */
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
    cout << "Time taken by function: "  << duration.count() << " milliseconds" << endl;

}